System and method for milking a group of dairy animals

ABSTRACT

A system for milking a group of animals, in particular cows, comprising an accommodation space in which the animals roam freely, and a plurality of fixed milking stations. A milk storage tank is placed outside the accommodation space. An automatic milking system for automated milking of the animals comprises at least one autonomous self-propelled trolley with milking cups. The milking system automatically connects the milking cups of the trolley to the teats of the animal. A milk discharge system connects the milking cups to the milk storage tank. The milk discharge system comprises flexible milk lines which are connected to the trolley. The trolley is connected to each milking station through a connection in an animal-free space adjacent to the milking stations. The flexible milk line is configured so the trolley can travel from the animal-free space into each of the milking stations while connected to the trolley.

The invention relates to a system and a method for milking a group ofmilking animals, in particular cows.

EP1188367 discloses a device for automatic milking of animals. Thedevice comprises an automatically movable master station and a number ofautomatically movable satellite stations. The master station comprisessuitable control equipment and a milk reservoir. Furthermore, the masterstation comprises navigation means and means for locating animals to bemilked. The master station can be moved automatically to a group ofanimals to be milked. The satellite stations comprise milking cups andmeans for connecting the milking cups. The satellite stations alsocomprise navigation means and means for locating animals to be milked.The satellite stations can locate, approach and possibly track theanimals to be milked in the vicinity of the master station. When theyhave assumed the correct position relative to the animal to be milked,the animal can be milked automatically. The satellite stations areconnected to the master station via flexible milk lines. Theself-propelled master station must deliver the milk from the milkreservoir to a milk storage tank. In view of the considerable size ofthe master station, delivering the milk to the milk storage tank isrelatively awkward. In addition, delivery of the milk takes time whichcannot be devoted to milking animals, which adversely affects theefficiency of the device. In addition, the milk lines from the satellitestations to the master station can become tangled with each other.Furthermore, the milk lines lie in the accommodation space in which theanimals walk around, which entails a risk of stumbling for the animals.

One object of the invention is to provide an improved system for milkinga group of milking animals.

This object is achieved according to the invention by a system formilking a group of milking animals, in particular cows, wherein thesystem comprises:

-   -   an accommodation space for the milking animals, which is        preferably stationary and/or has a fixed floor and/or is fenced        off,    -   a milk storage tank,    -   an automatic milking system for automatic milking of milking        animals,        wherein the milking system comprises at least one autonomous        self-propelled trolley with milking cups, and wherein the        milking system is configured for automatic connection of the        milking cups of the trolley to the teats of a milking animal,        and wherein the milking cups of the trolley are connected to the        milk storage tank by means of a milk discharge system, which        comprises at least one flexible milk line which, preferably at        one end thereof, is connected to the trolley and is in fluid        connection with at least one of the milking cups of the trolley,    -   a plurality of milking stations, preferably stationary milking        stations, which are each placed at a fixed location and next to        each other, preferably laterally next to each other, wherein the        milking stations each comprise an entry opening for entry of a        milking animal from the accommodation space to said milking        station,    -   an animal-free space which is closed for the milking animals in        the accommodation space and extends adjacent to the milking        stations, wherein the animal-free space is connected to each        milking station by means of a connection through which the        trolley can travel, and        wherein the milk storage tank is placed at a fixed location        outside the accommodation space, and the flexible milk line is        configured such that the trolley can travel from the animal-free        space into each of the milking stations while the milk line        remains connected to the trolley and/or the trolley remains        connected to the milk storage tank by means of the milk        discharge system with the milk line.

According to the invention, the milking animals can for example walkfreely around the accommodation space. The accommodation space isconfigured for keeping a production group of milking animals during thelactation phase. The accommodation space is preferably fenced off. Themilking stations each comprise an entry opening for entry of a milkinganimal from the accommodation space to said milking station. Eachmilking station is configured to receive a single milking animal at atime. The dimensions of the milking station are adapted to the lengthand width of a single milking animal. Only one milking animal at a timemay be present in each milking station.

The milking stations each comprise two long sides and two short sides.The entry opening of each milking station defines one of the short sidesof the milking station. The milking stations are preferably arrangedwith their long sides next to each other. For example, the milkingstations are separated from each other on their long sides by fixedseparating fences. Each milking station may be limited by a fence at theshort side opposite the entry opening. Behind the fence, for example,one or more feed and/or drinking troughs are arranged.

The animal-free space and the milking stations are connected to eachother such that the trolley can enter each milking station from theanimal-free space. In particular, the floor of each milking station onwhich a milking animal may stand is connected to the floor of theanimal-free space by a connection through which the trolley can travel.The trolley can travel from the floor of the animal-free space over saidfloor up to the floor of each milking station. The connection throughwhich the trolley can travel between the animal-free space and themilking stations extends under the fence. The trolley can travel fromthe animal-free space under the fence into each of the milking stations.

The trolley is self-propelled, i.e. the trolley comprises a drive andsteering system for driving and steering the trolley. The drive andsteering system preferably comprises at least one electric motor. When amilking animal visits one of the milking stations and is ready formilking, the milking system controls the autonomous self-propelledtrolley with the milking cups such that the trolley travelsautomatically over the floor of the animal-free space to the floor ofsaid milking station, up to below the teats of the milking animal.

During travel, the trolley remains connected to the milk storage tank bymeans of the flexible milk line and other components of the milkdischarge system, wherein in contrast to the prior art described above,the milk storage tank is not arranged in a master station which travelsautomatically through the accommodation space but is placed at a fixedlocation outside the accommodation space. The flexible milk line isconnected at one end to the trolley. The flexible milk line passesthrough the animal-free space. The configuration of the flexible milkline, in particular its length, diameter, stiffness and/or curvatureproperties, is such that the trolley can pass over the floor of theanimal-free space and reach the floor of all milking stations.

The flexible milk line is configured to enable the trolley to travelover the floor of the animal-free space to the floor of each of themilking stations, so that in each milking station the milking cups ofthe trolley can be connected to the teats of a milking animal present insaid milking station. The flexible milk line is adapted to give thetrolley a freedom of movement to be able to travel into each milkingstation, up to below the teats of a milking animal, while the trolleyremains connected to the milk storage tank by means of the flexible milkline and other components of the milk discharge system.

When the trolley has travelled to below the animal ready for milking,the milking cups of the trolley are automatically connected to the teatsof said milking animal. The milking animal is milked while the milkingcups are connected. The milk is discharged from the milking cups, viaone or more flexible milk lines and other components of the milkdischarge system, to the milk storage tank which is placed at a fixedlocation outside the accommodation space. Since the milk is dischargedto the milk storage tank, the trolley according to the invention neednot have its own milking tank. Thus the trolley according to theinvention may remain relatively compact. At the same time, with thesystem according to the invention no time is lost travelling to the milkstorage tank to deliver milk. Furthermore, the flexible milk line doesnot run through the accommodation space, whereby the milking animalswalking around the accommodation space are not obstructed by theflexible milk line or able to stumble over this.

According to the invention, it is possible that the milk dischargesystem is provided with a plurality of flexible milk lines which areeach connected at one end to the trolley and are each in fluidconnection with one of the milking cups, and a milk/air separator whichis arranged at a fixed location, preferably outside the accommodationspace, such as in the animal-free space, and wherein each milking cup ofthe trolley is connected respectively via one of the flexible milk linesto the milk/air separator, and wherein the flexible milk lines are eachconfigured such that the trolley can travel from the animal-free spaceinto each of the milking stations while the milk lines each remainconnected to the trolley and/or the trolley remains connected to themilk storage tank by means of the milk discharge system with the milklines.

Preferably, the trolley comprises four milking cups. The milking cupseach comprise a milk outflow opening which is in fluid connection with arespective one of the flexible milk lines, for example via a respectivemilk hose. A separate flexible milk line is provided for each of themilking cups. The flexible milk lines run from the trolley to thestationary milk/air separator. Both milk and air flow through the milklines and are received by the milk/air separator, in which the milk andair are separated from each other. The milk/air separator comprises amilk discharge opening which is connected by means of a milk transportline to the milk storage tank. A milk pump is arranged in the milktransport line for pumping the milk. The milk/air separator comprises anair outlet opening to which a vacuum line is connected.

The flexible milk lines form a string or bundle of milk lines,configured such that the trolley can travel from the animal-free spaceinto each milking station, up to below the teats of a milking animal tobe milked. Because the milk/air separator is not arranged on thetrolley, but for example in the animal-free space, the trolley canremain relatively compact. At the same time, the string of milk lines isconfigured such that the travelling trolley can reach all milkingstations while the milk lines remain connected to the trolley.

In a particular embodiment according to the invention, the milkdischarge system comprises a milk/air separator which is arranged on thetrolley, and wherein the milking cups are each connected to the milk/airseparator, for example by means of a respective milk-carrying hose, andwherein the milk/air separator comprises a milk discharge opening, whichis in fluid connection with the end of the flexible milk line connectedto the trolley, and wherein the trolley is provided with a milk pump forpumping milk via the flexible milk line to the milk storage tank. Onlymilk flows through the flexible milk line. Only one milk line isrequired for transporting the milk. Since the milk pump is arranged onthe trolley, the milk can be transported from the trolley to the milkstorage tank particularly efficiently. This entails an energy saving. Inaddition, the milk storage tank may be placed at a relatively greatdistance from the trolley.

In a preferred embodiment of the invention, the milking system comprisesa vacuum source which is arranged at a fixed location, preferably in theanimal-free space, wherein the vacuum source is connected via a vacuumsystem to the milking cups for applying a vacuum to the milking cups,and wherein the vacuum system comprises a flexible vacuum line which,preferably at one end thereof, is connected to the trolley and isconfigured such that the trolley can travel from the animal-free spaceinto each of the milking stations while the vacuum line remainsconnected to the trolley and/or the trolley remains connected to thevacuum source by means of the vacuum system with the vacuum pipe. Thevacuum source is for example formed by a vacuum pump. The vacuum systemmay comprise a pulsator which is arranged on the trolley, wherein theflexible vacuum line at one end thereof is connected to the pulsator.During milking, a substantially constant milking vacuum is maintained ina teat space of the milking cups, while by means of the pulsator apulsating vacuum pressure is applied in a pulsation space of the milkingcups. The teat space and the pulsation space of each milking cup areconnected to the vacuum source by the vacuum system. The flexible vacuumline of the vacuum system extends from the trolley through theanimal-free space and is configured to enable the trolley to travel overthe floor of the animal-free space to the floor of each of the milkingstations, such that in each milking station, the milking cups of thetrolley can be connected to the teats of a milking animal present in themilking station. Because vacuum is supplied to the trolley, the trolleyneed not have a vacuum pump, so the trolley remains simple and compact.At the same time, the vacuum line has sufficient length and flexibilityto allow the trolley to travel to all milking stations.

In one embodiment according to the invention, the milking systemcomprises an electric power supply source which is arranged at a fixedlocation, preferably in the animal-free space, and wherein the trolleyis connected to the power supply source by means of an electricalconnection, wherein the electrical connection comprises a power supplyline, which is connected at one end to the trolley and is configuredsuch that the trolley can travel from the animal-free space into each ofthe milking stations while the power supply line remains connected tothe trolley, and/or the trolley remains connected to the power supplysource by means of the electrical connection with the power supply line.The power supply source is for example a high-voltage current source.The power supply line is for example a flexible power supply cable. Thepower supply line connected to the trolley extends from the trolleythrough the animal-free space and is configured to enable the trolley totravel over the floor of the animal-free space to the floor of each ofthe milking stations, such that in each milking station, the milkingcups of the trolley can be connected to the teats of a milking animalpresent in the milking station. The trolley connected to the powersupply source requires no electrical accumulators to supply the electricmotors of the trolley with electrical energy. Due to the absence ofbatteries, the trolley can be designed lighter and more compact. Inaddition, the trolley need not be charged up and there is no risk ofloss of electrical power on the trolley because the batteries havedischarged. At the same time, the power supply line, in particular itslength, is configured such that during operation the trolley is notobstructed from travelling in each milking station under the teats of ananimal to be milked.

According to the invention, it is further preferred that the milkingsystem comprises a water connection which is arranged at a fixedlocation, preferably in the animal-free space, wherein the trolley isconnected to the water connection by means of a water supply systemcomprising a flexible water line, which is connected at one end to thetrolley and is configured such that the trolley can travel from theanimal-free space into each of the milking stations while the water lineremains connected to the trolley and/or that the trolley remainsconnected to the water connection by means of the water supply systemwith the water line. The water connection is connected to the watermains or to another water store. Water from the water connection can besupplied to the trolley by means of the water supply system. The wateris for example used to clean and/or rinse the milking cups and/or themilk discharge system. The trolley does not need to carry a water tankbecause the water is supplied to the trolley via the water supplysystem. Thus the dimensions of the trolley may remain compact and theweight of the trolley relatively low. In addition, it is not necessaryto top up with water because unlimited water is available on thetrolley. Thanks to the design with the flexible water line, the trolleycan furthermore still travel to all milking stations. The water lineextends from the trolley and is configured to enable the trolley totravel over the floor of the animal-free space to the floor of each ofthe milking stations, such that in each milking station, the milkingcups of the trolley can be connected to the teats of a milking animalpresent in the milking station.

Possibly, according to the invention, a cleaning agent such as steamand/or a disinfectant may be added to the water. In this case, it ispossible that the cleaning agent is added in the animal-free space andsupplied to the trolley via the water supply system. Alternatively, asteam generator and/or a tank for disinfectant may be arranged on thetrolley. In this way, the disinfectant may be added on the trolley tothe water supplied via the water hose.

According to the invention, it is possible that the milking systemcomprises a compressed air source which is arranged at a fixed location,preferably in the animal-free space, and wherein the trolley isconnected to the compressed air source by means of a compressed airsystem comprising a flexible compressed air line, which is connected atone end to the trolley and is configured such that the trolley cantravel from the animal-free space into each of the milking stationswhile the compressed air line remains connected to the trolley, and/orthe trolley remains connected to the compressed air source by means ofthe compressed air system with the compressed air line. By means of thecompressed air connection, compressed air can be supplied to thetrolley. On the trolley, compressed air may be used for example to blowout or evacuate the milking cups and/or the milk discharge system. Theflexible compressed air line extends from the trolley and is configuredto enable the trolley to travel over the floor of the animal-free spaceto the floor of each of the milking stations, such that in each milkingstation, the milking cups of the trolley can be connected to the teatsof a milking animal present in the milking station. The compressed airconnection does not hinder the trolley from serving all milkingstations.

In an embodiment according to the invention, the milking systemcomprises a control system, which may for example comprise a computer,laptop and/or smartphone, wherein the trolley is connected to thecontrol system by means of a hard-wired data connection comprising aflexible data line, which is connected at one end to the trolley and isconfigured such that the trolley can travel from the animal-free spaceinto each of the milking stations while the data line remains connectedto the trolley, and/or the trolley remains connected to the controlsystem by means of the hard-wired data connection with the data line.The data line comprises for example an Ethernet cable. Although the dataconnection according to the invention may be configured wirelessly, thequantity of data to be transferred from the trolley to the controlsystem and vice versa is sufficiently great for a hard-wired dataconnection to have advantages. In addition, a wireless connection is inpractice less reliable than a hard-wired connection, in particular in abarn for milking animals. The data line extends from the trolley and isconfigured to enable the trolley to travel over the floor of theanimal-free space to the floor of each of the milking stations, suchthat in each milking station, the milking cups of the trolley can beconnected to the teats of a milking animal present in the milkingstation. While the flexible data line remains connected to the trolley,the trolley can travel under the teats of an animal to be milked in allmilking stations.

According to the invention, it is possible that the milking system isprovided with a detection system for detecting the teats of a milkinganimal, wherein the detection system is provided with a camera, inparticular for making three-dimensional images, which is arranged on thetrolley and wherein the camera is connected to the control system forreceiving an image signal from the camera, and wherein the controlsystem is configured for determining the position of the teats on thebasis of the image signal received. The image signal from the camera maybe connected by means of the hard-wired data connection described aboveto the control system of the milking system.

In a preferred embodiment, the milking system comprises a, preferablystationary, coupling device which is arranged at a fixed location in theanimal-free space, wherein the trolley is connected to the couplingdevice by means of a flexible connecting string which is configured suchthat the trolley can travel from the animal-free space into each of themilking stations while the connecting string remains connected to thetrolley, and/or the trolley remains connected to the coupling device bymeans of the flexible connecting string, and wherein the connectingstring comprises the milk line and/or the milk lines and/or the vacuumline and/or the power supply line and/or the water line and/or thecompressed air line and/or the data line. Said one or more lines extendfor example through a flexible sleeve, such as a ribbed plastic tube.The one or more lines of the flexible string is/are connected to thetrolley at a first end and to the coupling device at the opposite secondend. The coupling device forms the connection of the one or more linesto the fixed world. By means of the coupling device, the milk lineand/or milk lines and/or vacuum line and/or power supply line and/orwater line and/or compressed air line and/or the data line of theflexible string are connected respectively to the milk storage tankand/or the vacuum source and/or the power supply source and/or the waterconnection and/or the compressed air source and/or the control system.Because several lines are held together in the flexible string, it isguaranteed that the trolley can travel unhindered over the floor of theanimal-free space to all milking stations.

Preferably, the coupling device comprises a first connector device,wherein the flexible connecting string, at an end remote from thetrolley, is provided with a second connector device which can bereleasably coupled to the first connector device for connecting the milkline and/or milk lines and/or the vacuum line and/or the power supplyline and/or the water line and/or the compressed air line and/or thedata line. When the first and second connector devices are coupledtogether, the one or more milking lines and the water line aresubstantially connected fluid-tightly, and the vacuum line andcompressed air line are substantially connected air-tightly. Theelectrical power supply line is connected electrically isolated. Thereleasable connection between the first and second connector devices hasadvantages for service and maintenance activities. If the trolleyrequires maintenance or fails, the trolley can easily be disconnected.In this case, it is also furthermore possible that the trolley is thenreplaced by another trolley. The trolley need not be maintained orrepaired on the farm, but can be collected or dispatched for maintenanceand/or repair. The system according to the invention can in the meantimeremain in operation with the replacement trolley.

In one embodiment, the animal-free space also comprises a floor whichextends below the level of the connection through which the trolley cantravel, whereby the animal-free space is lowered relative to the milkingstations. Maintenance of the trolley is now easy to perform becausepersonnel present on the floor of the animal-free space can easily reachthe level of the floor with the trolley. The invention is therefore verysuitable for converting existing milking pits and/or milking carousels,and making them suitable for milking with the automatic milking systemwith at least one autonomous, self-propelled trolley. The animal-freespace may also be a cellar which is provided with a roof which, at leastpartly, lies at the level of the floor of the accommodation space andconnects thereto, and via which the animals can walk from the milkingstation via the cellar roof to the accommodation space.

According to the invention, it is preferred that the animal-free spacecomprises a floor, wherein each milking station comprises a floorprovided with a first floor part which is connected, via a connectionthrough which the trolley can travel, to the floor of the animal-freespace, and a second floor part which is raised relative to the firstfloor part, and wherein the trolley is configured to travel from theanimal-free floor, at each milking station, under the second floor part,to the first floor part of said milking station and back. The length ofthe second floor part, viewed in the longitudinal direction of eachmilking station, is such that if a milking animal stands in said milkingstation with its front legs on the second floor part, while the rearlegs of said milking animal stand on the first floor part. The length ofthe second floor part is for example between 30-110 cm. The raisedsecond floor part is arranged for example 10-40 cm higher than the firstfloor part. Such a raised position corresponds substantially to thenormal height difference between a lying stall and the floor in a barn.The milking animals are easily able and accustomed to step up such aheight.

The trolley is designed such that the trolley can travel under theraised second floor part of each milking station, to under the teats ofa milking animal in the milking station in order to connect the milkingcups. The trolley can thus connect the milking cups to the teats of saidmilking animal efficiently and reliably. In addition, the milkingstations can be placed directly adjacent to each other, because thetrolley need not travel sideways between the front and rear legs inorder to reach the teats. This is particularly favorable for the visitof the milking animals to the milking stations, because the milkinganimals are herd animals which are more inclined to enter a milkingstation next to other milking animals.

According to the invention, it is preferred that the milking cups of thetrolley can be tilted between a retracted or collapsed or folded downstate, in which the trolley with the milking cups can travel under thesecond floor part, and an erected or folded up state, in which themilking cups are tilted up relative to the retracted state, inparticular are oriented substantially vertically upward. In order toallow the milking animals to take the step from the first to the secondfloor part easily and comfortably with their front legs, the secondfloor part is arranged relatively low. The height available between thefloor of the animal-free space and the underside of the raised secondfloor part is limited. In the erected state, the milking cups protrudeabove the underside of the second floor part. The milking trolley withthe erected milking cups cannot therefore travel below the second floorpart. The trolley comprises a tilt drive, which for example comprises anelectric drive motor, for tilting the milking cups from the erectedstate to the retracted state. The tilt drive is actively connected tothe control system of the milking system. To allow the trolley to travelfrom the floor of the animal-free space under the second floor part, themilking cups of the trolley are tilted into the retracted state, forexample into a substantially horizontal position. The trolley then fitsunder the second floor part. The trolley with the retracted milking cupscan therefore travel under the raised second floor part up to the firstfloor part, under the teats of a milking animal. Then the milking cupsare tilted into the erected state, whereupon the milking cups can beconnected to the teats of the milking animal.

In this case, it is possible that the milking stations comprise at leastone feed and/or drinking trough which is arranged at the head ends ofthe milking stations opposite the entry openings, such that a milkinganimal present in one of the milking stations must stand with its frontlegs on the second floor part of said milking station in order to eatand/or drink from the feed and/or drinking trough. By means of eatingand/or drinking, the milking animals are motivated to place their frontlegs on the second floor part. A milking animal which stands with itsfront legs on the second floor part has a position and/or an attitudewhich is suitable for connecting the milking cups of the trolley.Connection of the milking cups can therefore take place rapidly andprecisely.

In one embodiment, the system comprises an animal identification systemfor identifying each milking animal present in one of the milkingstations. For example, the animal identification system comprisestransponders which are arranged on each of the milking animals, and alsoreadout units for reading the transponders, wherein one of the readoutunits is arranged at each milking station. The readout units arepreferably arranged at the head end of each milking station. By means ofthe animal identification system, a milking animal visiting one of themilking stations can be identified. For example, by means of the controlsystem it can be established whether said milking animal complies with apredefined milking criterion, i.e. whether or not it should be milked.

In an embodiment according to the invention, the system comprises asecond autonomous, self-propelled trolley, which is provided with adevice for pretreatment and/or post-treatment of the teats of a milkinganimal present in a milking station. The second trolley can pretreat theteats of a milking animal in a milking station, for example clean,disinfect and/or stimulate these, before the first trolley connects themilking cups automatically to the teats. In addition or alternatively,the second trolley can be configured to post-treat the teats of themilked animal, i.e. after the first trolley has milked the milkinganimal and has travelled away, the second trolley travels under themilked animal for the post-treatment. Therefore, on the one hand thepretreatment and/or post-treatment, and, on the other hand the milking,are carried out by different trolleys. This increases the efficiency ofthe system. The first trolley may for example begin milking a followinganimal while the milked animal is post-treated by the second trolley.

Incidentally, the second trolley of the system according to theinvention may be configured in the same way as the first trolley. Thefirst trolley is then used for example for a first number of milkingstations, which are preferably situated next to each other, while thesecond trolley milks the milking animals in a second number of othermilking stations, which are preferably also situated next to each other.This further improves the efficiency of the system.

In one embodiment according to the invention, the milking stationscomprise at least three milking stations, preferably at least four orfive, or six or seven or eight milking stations. In particular, theratio between the number of milking animals to be kept in theaccommodation space and the number of milking stations is important. Ifthe accommodation space is configured to keep a predefined number ofmilking animals, the number of milking stations is preferably adapted tothe predefined number of milking animals, such that the system comprisesat least one milking station for every 20 milking animals, preferably atleast one milking station for every 15 milking animals, furtherpreferably at least one milking station for every 12 milking animals,and most preferably at least one milking station for every 10 milkinganimals. In other words, the accommodation space is preferablyconfigured to keep a group of a milking animals in the accommodationspace, while the milking stations comprise at least q milking stations,wherein a=q*b+r with 0 r b and b 30, preferably b 20 and more preferablyb 12, in particular b 10. The number of milking stations according tothe invention is relatively large. Thus in practice, it never occurs orrarely occurs that all milking stations are occupied by milking animalsat the same time. The number of milking stations according to theinvention is selected such that, in practice, almost always one or moremilking stations remain free. Thus the milking animals from the groupwalking around the accommodation space may enter such free milkingstations to eat and/or drink. The milking animals thus feel attracted tothe milking stations not merely because of the presence of feed and/ordrink, but also because milking animals are herd animals. The milkinganimals are more inclined to enter the milking stations if adjacentmilking stations are occupied by other milking animals. At the sametime, the milking stations in themselves are relatively inexpensive,because the relatively costly components of the milking system arearranged on the autonomous self-propelled trolley which is shared by allmilking stations. In this way the system according to the invention isparticularly suitable for attracting the milking animals effectively tothe milking stations and at the same time milking them efficiently.

The feature the accommodation space is configured to keep a predefinednumber of milking animals means that the accommodation space is designedto contain a predefined number of milking animals, such as 60-70 milkinganimals, during the lactation phase, wherein for example the surfacearea (m²) of the accommodation space and the number of facilities in theaccommodation space is adapted to the predefined number of milkinganimals to be kept. If the accommodation space comprises a resting areawith lying stalls, the number of lying stalls is for examplesubstantially equal to the number of milking animals to be kept, i.e. anaccommodation space for containing a group of for example 60 milkinganimals, preferably comprises approximately 60 lying stalls. In general,in such an accommodation space only one generally known milking robot isinstalled—a single milking robot for 60 milking animals is normal inpractice. According to the invention, the ratio between the number ofmilking stations and the number of lying stalls is however much greater.In one embodiment in which the rest area of the accommodation spacecomprises a number of lying stalls for the milking animals, the systemcomprises at least one milking station for every 20 lying stalls,preferably at least one milking station for every 15 lying stalls, morepreferably at least one milking station for every 12 lying stalls, andmost preferably at least one milking station for every 10 lying stalls,i.e. for example an accommodation space with 60 lying stalls comprises,according to the invention, 6 milking stations. The feed facilities ofthe accommodation space, such as one or more concentrate feedingstations and the length of the feed fence, are adapted to the number ofmilking animals to be kept in the accommodation space.

According to the invention, it is possible that the milking stations,viewed in top view, are designed elongate and arranged with the longsides laterally next to each other. Preferably, the milking stations areadjacent to each other. For example, the milking stations are arrangedparallel adjacent to each other laterally, i.e. the entry openings ofthe milking stations are substantially aligned relative to each other.The milking stations may however also be placed laterally next to eachother in an arc, in particular following a circle arc. It is possible inthis case that the long sides of the milking stations to some extent runtapering towards each other. The entry openings are preferably situatedon the short sides which extend along the outer periphery, while thefeed and/or drinking troughs are arranged on the short sides which lieon the inner periphery.

According to a second aspect, the invention relates to a system formilking a group of milking animals, in particular cows, wherein thesystem comprises:

-   -   an accommodation space for the milking animals, which is        preferably stationary and/or comprises a fixed floor and/or is        fenced off,    -   a plurality of milking stations, preferably stationary milking        stations, which are each arranged at a fixed position and next        to each other, preferably laterally next to each other, wherein        the milking stations each comprise an entry opening for entry of        a milking animal from the accommodation space to said milking        station, wherein the system comprises in particular at least        three milking stations, preferably at least four or five or six        or seven or eight milking stations and/or the number of milking        stations is as described in claim 16 and/or as above, and    -   an automatic milking system for automatic milking of milking        animals, wherein the milking system comprises milking cups and a        robot device which is movable relative to the milking stations,        such that in each milking station, by means of the robot device,        milking cups can be connected automatically to the teats of a        milking animal present in said milking station.

A milking stall with a milking robot is generally known. In the priorart, normally the aim is to achieve as high a utilization level aspossible of a milking robot. The milking robot is relatively expensive,so its capacity must be utilized as optimally as possible. With thesystem according to the invention, the number of milking stations ispreferably such that, in practice, almost always one or more milkingstations are free. Nonetheless, the system according to the invention isprofitable because relatively costly components are shared by severalmilking stations. The robot device according to the invention is movableto be able to connect milking cups in every milking station, wherebyeach milking station need not have its own robot device. The costs permilking station according to the invention are relatively low due to theuse of a common robot device for the milking stations. Thus there is noeconomic obstacle to having free milking stations, and the system caneconomically be designed with an excess number of milking stations.

According to the second aspect of the invention, the robot device can beconfigured in various ways. In one embodiment, the robot devicecomprises an autonomous, self-propelled trolley, wherein the milkingcups are arranged on the trolley, and wherein the trolley is configuredto travel to each milking station, and wherein the trolley is configuredfor automatic connection of the milking cups of the trolley to the teatsof a milking animal present in the milking station. The milking trolleymay be configured as described above. For example, each milking stationcomprises a floor on which a milking animal can stand, and the systemfurthermore comprises an animal-free space which extends on the side ofthe milking stations opposite the accommodation space, wherein theanimal-free space comprises a floor which is connected to the floor ofeach milking station via a connection through which the trolley cantravel. Initially for example, the trolley is on the floor of theanimal-free space. When a milking animal must be milked in one of themilking stations, the milking system controls the trolley such that thetrolley automatically travels over the floor of the animal-free space tothe floor of said milking station, up to below the teats of the milkinganimal. The trolley is autonomous and self-propelled, i.e. the trolleycomprises a drive and steering system for driving and steering thetrolley. The drive and steering system preferably comprises at least oneelectric motor. When the trolley has travelled to below the animal readyfor milking, the milking cups are automatically connected to the teatsof said milking animal. The milking animal is milked while the milkingcups are connected. After the milking animal has been milked, thetrolley can travel back to the floor of the animal-free space. Thetrolley is then again ready for a following milking in another orpossibly the same milking station.

In an alternative embodiment, the robot device according to the secondaspect of the invention comprises a robot arm, which is provided with afirst arm part which is movably connected to a fixed supportingstructure, and at least one second arm part which is movably connectedto the first arm part. For example, the first arm part is connected tothe supporting structure pivotably about a substantially vertical pivotaxis, for example by means of a ball joint, wherein the second arm partis connected telescopically movably to the first arm part. In this case,the milking stations may be positioned around the pivot axis, i.e. themilking stations then lie laterally next to each other following acircle arc, such that the milking stations are oriented with their headsides towards the pivot axis. By moving the first arm part about thepivot axis, the robot arm can be aligned with each of the milkingstations for connecting the milking cups in each milking station. Therobot arm may however also be guided movably along a guide rail whichextends transversely relative to the long sides of the milking stationsarranged next to each other. In this case, the robot arm is movablerectilinearly along the guide rail, so that the robot arm can connectthe milking cups in each milking station. Such a robot arm forconnecting milking cups may be designed and produced reliably usingtechniques known in themselves in practice.

According to the invention, it is possible that the robot arm isprovided with the milking cups. The milking cups are arranged on therobot arm. The milking cups are connected to the robot arm, and therobot arm can connect the milking cups of the robot arm one by one tothe teats of a milking animal. Such a robot arm may be produced and usedparticularly reliably.

In addition, it is possible that the milking system is provided with amilking cup holder which is configured for receiving milking cups whichare not being used, wherein the robot arm is provided with at least onegripper member which is configured to take at least one milking cup fromthe milking cup holder, and connect it to a teat of a milking animalpresent in one of the milking stations. In this case, the robot armtakes a first milking cup from the milking cup holder and connects saidmilking cup to a teat, then the robot arm takes a second milking cupfrom the milking cup holder, and so on. Such a robot arm is comparableto a robot arm of a generally known milking robot and may be producedand used reliably.

Each milking station may comprise a set of milking cups for connectionto the teats of a milking animal present in said milking station. Also,the milking cups may for example be arranged in sets in the animal-freespace in front of each milking station. It is also possible that acommon set of milking cups is shared by several milking stations. Themilking cups are then used successively in several milking stations.

In a preferred embodiment according to the second aspect of theinvention, the system comprises an animal-free space which is closed forthe milking animals in the accommodation space and extends adjacent tothe milking stations, wherein the animal-free space comprises a floor,and wherein each milking station comprises a floor which is providedwith a first floor part and a second floor part which is raised relativeto the first floor part, and wherein the robot device is configured tomove from the floor of the animal-free space at each milking station,under the second floor part, to the first floor part of said milkingstation and back. In this case, it is possible that a milking cup ormilking cups, which for example are connected to a robot deviceconfigured as a robot arm or are held by a gripper member of a robotarm, can be moved between a retracted or collapsed or folded down statein which the robot device with said milking cup or milking cups can movebelow the second floor part, and an erected or folded up state in whichsaid milking cup or milking cups are tilted up relative to the retractedstate. The robot device with retracted milking cup or milking cups fitsunder the second floor part. The robot device can move under the raisedsecond floor part up to the first floor part, under the teats of amilking animal. It is then possible to tilt said milking cup or milkingcups up into the erected state to be connected to the teats of saidmilking animal. The feature of claim 14 may also be applied here.

According to the second aspect of the invention, it is furthermorepossible that the system comprises a milk storage tank which is placedat a fixed location outside the accommodation space, wherein the milkingcups are connected to the milk storage tank by means of a milk dischargesystem which comprises at least one flexible milk line, wherein theflexible milk line is configured such that the robot device can movefrom the animal-free space into each of the milking stations while themilk line remains connected to the robot device and/or the robot deviceremains connected to the milk storage tank by means of the milkdischarge system with the milk line. In this case, one or more of thefeatures according to claims 2-10 may be applied, wherein the trolleymay however also be a robot arm or other robot device. The propertiesand advantages of the trolley described above may also be achieved witha robot arm or other robot device.

The invention also relates to a method for milking a group of milkinganimals, in particular cows, in a system as described above, wherein themethod comprises:

-   -   identification of a milking animal in one of the milking        stations,    -   determining whether said milking animal complies with a        predefined milking criterion,    -   if said milking animal complies with the predefined milking        criterion:        -   moving a robot device, for example a trolley or robot arm,            from the animal-free space to said milking station, in            particular from the floor of the animal-free space to the            floor of the milking station,        -   automatic connection of milking cups by means of the robot            device to the teats of said milking animal,        -   milking of said milking animal in said milking station by            means of the milking system while the milking cups are            connected to the teats of said milking animal,        -   disconnection of the milking cups from the teats of said            milking animal after the milking of said milking animal is            completed,        -   moving the robot device from said milking station back to            the animal-free space.

When a milking animal which fulfils the milking criterion enters one ofthe milking stations, said milking animal is identified and secured.With a robot device which is configured as a trolley, the trolley thentravels from the animal-free space to said milking station until thetrolley is below the teats of said milking animal. The milking cups ofthe trolley are connected automatically to the teats of said milkinganimal and the milking animal is then milked. The milk is discharged viathe flexible milk line and transported to the milk storage tank. Afterthe milking process is completed, the milking cups are disconnected andthe trolley then returns to the animal-free space. When later anothermilking animal which fulfils the milking criterion enters another orpossibly the same milking station, the trolley travels to said milkingstation to milk said other milking animal. For example, the milk isdischarged via the milk discharge system with the flexible milk line tothe milk storage tank, so that the trolley according to the inventioncan remain relatively compact and no time need be spent travelling tothe milk storage tank to deliver the milk. At the same time, the trolleyis able to milk the milking animals in all milking stations efficiently.

The invention will now be explained in more detail below with referenceto the attached drawing.

FIG. 1 shows a diagrammatic top view of a first embodiment of a systemaccording to the invention.

FIG. 2 shows an enlarged detail II of FIG. 1.

FIGS. 3a and 3b show perspective views of one of the milking stations ofthe system shown in FIG. 1, wherein the neck lock device is respectivelyin the free state and in the locked state.

FIGS. 3c and 3d show front views of the milking station shown in FIGS.3a and 3 b.

FIGS. 4a-4d show side views of one of the milking stations of the systemshown in FIG. 1, in which a milking animal is secured and milked.

FIG. 5 shows a diagrammatic top view of a second embodiment of a systemaccording to the invention.

FIGS. 6a-6c show side views of one of the milking stations of the systemshown in FIG. 5, in which a milking animal is secured and milked.

FIG. 7 shows a side view in cross section along line VII-VII from FIG. 4a.

Several inventions are contained in the exemplary embodiments shown. Inthis description of the figures, several inventions and features thereofare described. Although the exemplary embodiments show these features incombination, these features have significance alone, i.e. these featurescan be applied independently of each other. In addition, a systemaccording to the invention need not have all features in combination; asystem according to the invention may also contain only a number ofthese features. In other words, a system according to the invention maycontain all possible combinations of one or more of these features.

The system shown in FIG. 1 for milking a group of milking animals, inthis exemplary embodiment cows 8, is indicated as a whole with 1. Thesystem 1 comprises an accommodation space 2 which is fenced off by wallsor fencing 3 a, 3 b, 3 c and a feed fence 4. The accommodation space 2is stationary, i.e. immovable, in particular non-rotatable. Theaccommodation space 2 comprises a fixed floor 5, for example a gratingor grid floor or a solid floor. The accommodation space 2 is formed by abarn space, i.e. the cows 8 are inside the barn. The accommodation space2 may be connected via a selection gate to another accommodation spacesuch as a separation space or a grazing space (not shown).

The accommodation space 2 comprises a feed area for feeding the milkinganimals, which in this exemplary embodiment is formed by a feed fence 4and a concentrate feeding station 6. The accommodation space 2 comprisesa rest area for resting the cows 8. In this exemplary embodiment, therest area is formed by lying stalls 9 in which the cows 8 can lie down.The rest area may however also be configured without lying stalls.

The accommodation space 2 is configured to keep a predefined number ofcows during the lactation phase. The surface area (m²) of theaccommodation space 2 and the facilities in the accommodation space 2are adapted to the predefined number of cows to be kept. Since almostall cows rest overnight in the accommodation space, in general one lyingstall 9 per cow 8 for example is considered the norm, i.e. the number oflying stalls 9 is substantially equal to the number of cows to becontained. In this exemplary embodiment, the accommodation space 2 isconfigured to keep 60 cows, and the accommodation space 2 thereforecomprises 60 lying stalls. Also, for example, the feed facilities of theaccommodation space 2, such as the length of the feed fence 4, areadapted to the number of cows to be contained in the accommodation space2. In this exemplary embodiment, the system 1 comprises six milkingstations 10, i.e. there is one milking station per ten cows 8. Thenumber of milking stations 10 may however be greater or smaller, forexample the system 1 may also have seven or eight milking stations 10,or four or five milking stations 10. If the accommodation space 2 isconfigured for more or fewer than 60 cows 8, the number of milkingstations 10 is adapted accordingly. The number of milking stations 10 ismatched to the number of milking animals to be kept, such that thesystem 1 comprises at least one milking station 8 for every 20 milkinganimals 8, preferably at least one milking station 10 for every tenmilking animals 8.

The milking stations 10 are each arranged at a fixed location andlaterally next to each other. Each milking station 10 has two long sidesand two short sides; the milking stations 10 are each elongate. Themilking stations 10 are arranged with the long sides laterally adjacentto each other (see FIGS. 1 and 2). In FIGS. 1 and 2, the milkingstations 10, seen in top view, are substantially rectangular. Themilking stations 10 may however also be configured differently. Forexample, the milking stations may be placed next to each other followinga circle arc (not shown).

The milking stations 10 are mutually separated by separation fences 12formed by a horizontal and a vertical bar part 13 a, 13 b (see FIGS. 2,3 a and 3 b). The horizontal bar part 13 a is relatively low, forexample around 60-120 cm high. The cows 8 in adjacent milking stations10 stand closely next to each other and have mutual contact because themilking stations 10 are only separated from each other by the openseparation fences 12. In this way, the herding behavior of the cows inthe milking stations 10 is reinforced.

The milking stations 10 each comprise an entry opening 11 for entry of acow 8 from the accommodation space 2 to the milking station 10. Theentry opening 11 of each milking station 10 is arranged on one of theshort sides of the milking station 10. As shown most clearly in FIGS. 2,3 a and 3 b, none of the milking stations 10 has an access gate which isoperated by an actuator device between an open state in which the entryopening 11 is open, and a closed state in which the entry opening 11 isclosed. The entry openings 11 of the milking stations 10 are each openpermanently. Incidentally, according to the invention, it is notexcluded that a milking station is taken out of use by closing the entryopening of that milking station, so that the milking station is nolonger accessible to milking animals, for example for maintenance orcleaning activities in that milking station. During normal operation,the entry openings 11 are however permanently open. If a milking station10 is not occupied by a cow 8, there is no obstacle to one of the cows 8entering said milking station 10 from the accommodation space 2. Theunoccupied milking stations 10 are totally freely accessible for thecows 8.

On the short sides or head ends opposite to the entry openings 11, themilking stations 10 are mutually aligned along a fixed fence 14 (seeFIG. 2). In this exemplary embodiment, the fence 14 for each milkingstation 10 has two fence parts 15 a, 15 b which, viewed in thetransverse direction of the milking station 10, are arranged spacedapart from each other, leaving free a central opening 19 with a firstwidth w₁ such that the neck of a cow 8 can pass through as far as theshoulders. A cow 8 can enter a milking station 10 until the shoulders ofthe front legs of the cow 8 come to rest against the fence parts 15 a,15 b on either side of the central opening. Since the fence parts 15 a,15 b are arranged fixedly, a cow 8 can only leave each milking station10 by walking backward again through the entry opening 11. The entryopening 11 therefore also forms an exit opening.

Each milking station 10 furthermore comprises a neck lock device 18which, in this exemplary embodiment, is arranged on the fence parts 15a, 15 b. The neck lock device 18 of each milking station 10 can beoperated by an actuator device 40 between a locked state or securedstate (see FIGS. 3b and 3d ), in which a cow 8 in the milking station 10is held by the neck and hence secured and/or held in the milking station10, and an open state (see FIGS. 3a and 3c ), in which a cow 8 is freeto move its head in and out of the neck lock device 18 and is free toleave the milking station 10. Thus the neck lock device 18 of eachmilking station 10 can be actively operated. The neck lock device 18will be described in more detail below.

In this exemplary embodiment, the milking stations 10 have a drinkingsystem 16 which is configured to provide water for the milking animals8. The drinking system 16 comprises a plurality of drinking troughs 17;each milking station 10 is provided with its own drinking trough 17. Thedrinking troughs 17 are connected by a pipe system to a water supply,for example a water mains connection. Water from the water mainsconnection is supplied via the pipe system to the drinking troughs 17.The water in the separate drinking troughs 17 remains relatively fresh,which is favorable for the drinking behavior of the milking animals. Itis however also possible that several milking stations 10 have a commondrinking trough, or even that a single drinking trough is provided forall milking stations 10 (not shown).

The drinking trough 17 of each milking station 10 is positioned at adistance behind the fence parts 15 a, 15 b of said milking station 10,such that a cow 8 in said milking station 10 must push its head and neckthrough the central opening 19 between the fence parts 15 a, 15 b, andthrough the neck lock device 18 in the open state, in order to drinkwater from the drinking trough 17. In other words, the drinking system16 is configured such that water can only be reached by a cow 8 in amilking station 10 which has pushed its head and neck through the necklock device 18 in the open state. In this way, a cow 8 in a milkingstation 10 which wishes to drink is secured safely and reliably at theneck by the neck lock device 18 of said milking station 10. This will beexplained further below.

In order to identify the cows in the milking stations 10, the system 1has an animal identification system, known in itself, for identifyingeach milking animal which visits one of the milking stations. The animalidentification system comprises for example transponders 23 which areattached to collars worn by the cows 8, and readout units 24 for readingthe transponders 23. The readout units 24 are arranged at the head endof each milking station 10, in particular along the fence 14 (see FIG.2). When a cow 8 walks into one of the milking stations 10 and thenpushes its head through the fence 14, the transponder 23 in the collarof the cow 8 is read by the readout units 24 of said milking station 10,so that the cow 8 is identified. A control system 41, for examplecomprising a computer, laptop and/or smartphone, is actively connectedto the readout units 24. The identity of the identified cow 8 is enteredin the control system 41.

The cows can be milked in the milking stations 10 by an automaticmilking system 20. With an automatic milking system, the cowsvoluntarily go to the milking stations 10 to be milked. The automaticmilking system 20 comprises milking cups 22. The milking system 20 isconfigured to connect the milking cups 22 automatically to the teats ofa cow 8 in a milking station 10, and to milk said cow 8 automaticallyprovided that said cow 8 complies with a predefined milking criterion,i.e. is ready for milking. The milking system 20 comprises the controlsystem 41 or is actively connected therewith. The control system 41determines whether a cow 8 which is identified on a visit to a milkingstation 10 fulfils the milking criterion, i.e. must be milked. Differentmilking criteria are possible, for example on the basis of the timewhich has elapsed since the last milking of the cow, or on the basis ofthe expected milk yield, which is dependent on the time since the lastmilking and the milk production rate in the udders, which can becalculated from historical data from previous milkings of the cow, orstill other milking criteria.

The milking stations 10 are placed adjacent to an animal-free space 70which is closed for the milking animals present in the accommodationspace 2. The animal-free space 70 forms a “clean” space, i.e. the cows 8have no access to the animal-free space 70 and cannot walk there. Theanimal-free space 70 has a substantially flat floor 71. Variouscomponents of the milking system 20 are arranged in the animal-freespace 70. This will be explained further below.

The automatic milking system 20 comprises a robot device which ismovable relative to the milking stations 10 such that, in each milkingstation 10, milking cups 22 can be connected automatically by means ofthe robot device to the teats of a cow 8 present in said milking station10. The robot device may be configured in various ways, for example asan autonomous self-propelled trolley with milking cups 22 (see FIGS. 1,2 and 4 a-4 d) or as a robot arm (see for example FIGS. 5 and 6 a-6 c).The various embodiments of the automatic milking system 20 will bedescribed in more detail below.

In the exemplary embodiment shown, the drinking system 16 of the milkingstations 10 is the only drinking facility for the cows in theaccommodation space 2. In other words, the cows in the accommodationspace 2 can only drink from the drinking troughs 17 of the milkingstations 10. In order to drink, the cows must visit the milking stations10. Since the cows 8 must always drink water, the visit frequency to themilking stations 10 is more than sufficient for milking two or threetimes per day by means of the automatic milking system 20. Thus it isnot necessary or scarcely necessary to collect the cows manually formilking. This is a particularly great advantage since, in the prior art,collecting cows which do not voluntarily visit a milking robot, requiresmanual labor.

Although the cows can only drink in the milking stations 10, at the sametime the water intake of the cows necessary for milk production isguaranteed. The number of milking stations 10 according to the inventionis relatively great. As indicated above, the accommodation space 2 inthis exemplary embodiment is configured to keep a predefined number of60 milking animals. In the prior art, it is normal to place only onemilking robot in such a production group. According to the inventionhowever, six milking stations 10 are provided. With such a number ofmilking stations, in practice it does not occur or rarely occurs thatall milking stations 10 are occupied by cows simultaneously. Even ifcows not ready for milking occupy milking stations 10 for drinkingwithout being milked, almost always one or more milking stations 10remain free in which other cows can drink. Consequently, it isguaranteed that the cows always or almost always have unrestrictedaccess to water.

At the same time, it is economically viable to have a relatively largenumber of milking stations 10 because the costs per milking station 10are particularly low, since the relatively costly components of theautomatic milking system 20, i.e. the robot device, are shared by themilking stations 10. The robot device is movable relative to the milkingstations 10 such that, in each milking station 10, milking cups 22 canbe connected automatically by means of the robot device to the teats ofa cow 8 present in said milking station 10.

The drinking system 16 of the milking stations 10 is furthermoreconfigured to make water available, in particular in unlimitedquantities (ad libitum), for each cow present in one of the milkingstations 10, irrespective of whether or not said cow 8 fulfils themilking criterion. In other words, each cow visiting one of the milkingstations 10 can drink in said milking station 10, irrespective ofwhether or not said cow 8 is ready for milking. In this way, the cowsare conditioned to associate the milking stations 10 primarily withdrinking, and only secondarily with milking. The milking stations 10form drinking stations for the cows. Consequently, the cows 8 arefurther encouraged to visit the milking stations 10 voluntarily.

To facilitate the access to water further, the permanently open entryopenings 11 of the milking stations 10 can be reached freely and/orunhindered via a walkable connection from the feed fence 4, theconcentrate feeding station 6 and from the lying stalls 9 in theaccommodation space 2. The accommodation space 2 is configured such thatthe cows can walk around freely in the accommodation space 2 between thefeed fence 4, the lying stalls 9 and each entry opening 11. Totally freecow traffic is possible between the feed fence 4, the lying stalls 9 andthe entry openings 11. To drink water, the cows in the accommodationspace 2 are able to walk to the drinking system 16 of the milkingstations 10 without compulsion and without hindrance.

Therefore with the system according to the invention, not only is itguaranteed that every cow 8 visits the milking stations 10 frequently,whereby no cows or few cows need be collected for milking, but alsowater is available so easily that the water consumption of the cows iscomfortably sufficient for optimum milk production.

Although, in this exemplary embodiment, the drinking system 16 is theonly drinking facility for the cows 8 in the accommodation space 2, thesystem according to the invention may comprise a further drinkingfacility, for example a drinking trough in the accommodation space 2.The capacity of the further drinking facility is then however selectedsmall enough that, in order to meet their daily water needs, the cowsmust still visit the milking stations 10.

In this exemplary embodiment, the neck lock device 18 of each milkingstation 10 (see FIGS. 3a-3d ) comprises two retaining posts 43 a, 43 b,which are each pivotable about a respective pivot axis A (see also FIG.2) which runs substantially in a horizontal plane, obliquely relative tothe longitudinal direction of the milking station 10. The pivot axes Aof the retaining posts 43 a, 43 b are for example arranged at a heightof 30 cm. The angle between the pivot axis A of each retaining post 43a, 43 b and the longitudinal direction of the milking station 10 isaround 30° in this exemplary embodiment.

As shown in FIGS. 3a and 3c , in the open state of the neck lock device18, the retaining posts 43 a, 43 b define a V-shaped opening. A cow 8walking into the milking station 10 first pushes its head through thecentral opening 19 between the fence parts 15 a, 15 b, and through theV-shaped opening to reach the drinking trough 17. The V-shaped openingis relatively large so that the cow 8 is encouraged to drink from thedrinking trough 17. In the locked state shown in FIGS. 3b, 3d , theretaining posts 43 a, 43 b run substantially vertically. Between them isa retaining opening with a second width w₂ which is smaller than thefirst width w₁ of the central opening 19 between the fence parts 15 a,15 b. The width w₂ of the retaining opening is such that a cow 8 whichpushes its head through the retaining opening cannot then withdraw it.

The width w₂ of the retaining opening is for example 195 mm. With such awidth w₂, a cow 8 locked at the neck cannot withdraw its head fully fromthe retaining opening, but can still move to some extent in thelongitudinal direction of the milking station 10. This freedom ofmovement is however limited by the fence parts 15 a, 15 b which form astop for the shoulders of the cow 8. The cow 8 can only move its neckforward through the retaining opening until the shoulders of its frontlegs come to lie against the fence parts 15 a, 15 b. By restricting thefreedom of movement of the cow in the milking station 10, the automaticconnection of the milking cups 22 to the teats of the cow 8 becomeseasier.

The retaining posts 43 a, 43 b are each connected to one of the fenceparts 15 a, 15 b by means of a hinge arm 44 a, 44 b. Each hinge arm 44a, 44 b consists of two arm parts 45 a, 46 a and 45 b, 46 brespectively, which are mutually pivotably connected by means of a hinge48. As described above, the neck lock device 18 is actively movable bymeans of the actuator device 40 between the locked state (see FIGS. 3band 3d ) and the open state (see FIGS. 3a and 3c ). In this exemplaryembodiment, the actuator device 40 of each neck lock device 18 comprisestwo pneumatic cylinders 42 a, 42 b for moving the respective retainingposts 43 a, 43 b. To control the pneumatic cylinders 42 a, 42 b, theseare actively connected to the control system 41.

The pneumatic cylinders 42 a, 42 b engage one of the arm parts 45 a, 45b of the hinge arms 44 a, 44 b. The other arm parts 46 a, 46 b eachcomprise a protruding lip 47 which forms a stop for the locked state.When the pneumatic cylinders 42 a, 42 b are extended, the retainingposts 43 a, 43 b move from the open state to the locked state, wherein,because of the obliquely running pivot axes A, the retaining posts 43 a,43 b at the same time move slightly forward. When the cow 8 is enclosed,the retaining posts 43 a, 43 b approach the neck of the cow 8 not onlyfrom the side but also to some extent from the rear, so that the cow 8does not or scarcely perceives the movement of the retaining posts 43 a,43 b, even from the corner of its eye. This helps keep the cow 8 quietduring application of the neck lock.

The pneumatic cylinders 42 a, 42 b push the arm parts 45 a, 45 b througha dead point until the lips 47 of the arm parts 46 a, 46 b come to lieagainst the arm parts 45 a, 45 b. The retaining posts 43 a, 43 b havethen reached the locked state. The pneumatic cylinders 42 a, 42 b neednot be dimensioned to absorb, in the locked state, forces which the cow8 may exert to free itself from the neck lock. Such forces aredissipated mechanically via the hinge arms 44 a, 44 b. To open the necklock 18, the retaining posts 43 a, 43 b are retracted again through thedead point by the pneumatic cylinders 42 a, 42 b.

As described above, the drinking troughs 17 of the drinking system 16are configured to provide water for the cows 8. In this exemplaryembodiment, each drinking trough 17 is provided with a flap or tongue49, known in itself and operated by the cow, which forms a supply valve.The flap 49 is pretensioned in a closed state. When a cow 8 presses itsnose against the flap 49, the flap 49 is moved to an open state andwater flows into the drinking trough 17. A sensor 50, for example a flowmeter, is provided in the supply line to the drinking trough 17 (seeFIGS. 4a-4d ). The sensor 50 is actively connected to the control system41. On the basis of the sensor 50, it is perceived when the cow 8presses its nose against the flap 49. The sensor 50 forms a detectionmeans for detecting whether the cow 8 in a milking station 10 has pushedits head into the drinking trough 17 of said milking station 10. Thedetection means may however also be configured differently, for examplewith a sensor for detecting whether a light beam is interrupted. It isalso possible that the detection means is configured to detect whetherthe cow in a milking station 10 has brought its head above the drinkingtrough 17, instead of in the drinking trough 17.

In this exemplary embodiment, the sensor 50 configured as a flow metermeasures the quantity of water supplied to each drinking trough 17. Onthe basis of the quantity of water supplied, the control system 41 candeduce how much water the cows 8 have drunk during a visit to themilking station 10. Therefore the water consumption and drinkingbehavior of the cows 8 can be monitored individually.

A cow 8 which visits the milking station 10 to drink water from thedrinking trough 17 pushes its head through the V-shaped opening betweenthe retaining posts 43 a, 43 b. The transponder 23 in the collar of thecow 8 is read by the readout unit 24 of said milking station 10, so thatthe cow 8 is identified. Although the readout unit 24 can indeedidentify the cow 8 by means of the transponder 23, it cannot beaccurately established whether the cow 8 is in the correct positionand/or attitude for locking at the neck in the milking station 10. Thecorrect position and/or attitude in the milking station 10 can howeverbe established using the sensor 50. When, after identification by thetransponder 23, the cow 8 operates the flap 49 of the drinking trough 17with its nose, the control system 41 via the sensor 50 establishes thatthe head of the cow 8 is in the drinking trough 17 and the cow 8therefore has a position and/or attitude in the milking station 10 whichis suitable for locking the cow 8 at the neck by means of the neck lockdevice 18 of said milking station 10.

When the control system 41 has established that the cow 8 in the milkingstation 10 has a position and attitude which is suitable for lockingsaid cow 8 at the neck, the control system 41 controls the actuatordevice 40 of said milking station 10 such that the cow 8 is locked atthe neck. The control system 41 for controlling the pneumatic cylinders42 a, 42 b is configured and programmed such that the retaining posts 43a, 43 b are only moved from the open state to the locked state if thereadout unit 24 has identified the transponder of the cow 8 andestablished, on the basis of the sensor 50, that the cow 8 is pressingits nose against the flap of the drinking trough 17, i.e. the cow 8 isin the position and attitude in the milking station 10 in which the cow8 can be reliably enclosed between the retaining posts 43 a, 43 b. Inother words, the control system 41 makes use of the combination of thedata from the transponder 23/readout unit 24 and the sensor 50 todetermine whether the cow 8 in the milking station 10 has the positionand attitude suitable for the neck lock.

On readout of the transponder 23 of a cow 8, the control system 41furthermore determines whether or not the identified cow 8 fulfils themilking criterion, i.e. is/is not ready for milking. According to theinvention however, these data are not used to operate the retainingposts 43 a, 43 b from the open state to the locked state. According tothe invention, locking the cow 8 at the neck is not dependent on whetherthe cow 8 fulfils the milking criterion. It is not relevant whether thecow 8 is ready for milking or not: both a cow ready for milking and acow not ready for milking are locked by the retaining posts 43 a, 43 bof the neck lock device 18. The control system 41 is programmed suchthat all cows 8 which, on a visit to the milking station 10, assume theposition and attitude suitable for the neck lock in the milking station10, are locked at the neck by means of the neck lock device 18. Each cow8 which walks into a milking station 10 and then operates the flap 49 ofthe drinking trough 17 with its nose, is according to the invention thensecured at the neck by the retaining posts 43 a, 43 b.

Because the cows 8 are always locked at the neck when, after walkinginto a milking station 10, the cows 8 begin to drink from the drinkingtrough 17, the cows 8 rapidly become accustomed to the neck lock 18.Consequently, the cows 8 stand quietly in the milking station 10 whenthe cows 8 are held at the neck. This is favorable for calmness in theherd, and furthermore has the particularly great advantage that themilking system 20 can easily and quickly automatically connect themilking cups 22 in the case that the cow 8 is ready for milking.

If the cow 8 locked at the neck is not ready for milking, this cow 8need not be milked. After locking at the neck, the cow 8 may be releasedagain almost immediately. The control system 41 is configured to releaseevery cow 8 not ready for milking after a predefined period, calculatedfrom the time at which the cow 8 is locked at the neck. The predefinedperiod in this exemplary embodiment is around 15 seconds, but may belonger or shorter of course.

If the cow 8 locked at the neck is ready for milking, the control system41 sends a signal to the milking system 20 to milk said cow 8. Thecontrol system 41 is programmed such that the neck lock device 18remains locked until the milking of the cow 8 is completed. Only whenthe milking cups have been disconnected is the neck lock device operatedby the control system 41 from the locked state to the open state, torelease the cow 8. It is preferred that the neck lock device 18 isopened only around 5-30 minutes after disconnection of the milking cups22. During this period, the teat openings of the milked cow 8 canrecover.

As described above, in this exemplary embodiment, the entry openings 11of the milking stations 10 are permanently accessible for the milkinganimals 10. The feature of always locking the cows 8 at the neck howevermay also be used in a system with milking stations which for examplecomprise an access gate (not shown). In this case, the system accordingto the invention is preferably configured such that the entry opening 11of each milking station 10 which is not occupied by milking animal, isleft open to allow a cow 8 into the milking station 10, irrespective ofwhether the cow 8 fulfils the milking criterion. In other words, if theentry openings 11 of the milking stations 10 can be closed by an accessgate (not shown), the access gates are operated by the control system 41so that each access gate of an unoccupied milking station 10 remainsopen. Every cow 8, irrespective of whether or not the cow complies withthe milking criterion, can walk into the free milking station 10.

In the exemplary embodiment shown in FIGS. 1, 2 and 4 a-4 d, the robotdevice of the automatic milking system 20 is configured as an autonomousself-propelled trolley 21 for connection of the milking cups 22, whereinthe trolley 21 is connected to the fixed world by means of a flexibleconnecting string 5 containing one or more pipes or lines.

The trolley 21 is connected by means of the flexible connecting string35 to a coupling device 36 which is arranged at a fixed location in theanimal-free space 70, for example on a wall of the barn, i.e. theconnecting string 35 is connected at one end to the trolley 21 and atthe other end to the coupling device 36. The coupling device 36comprises a first connector device, while the flexible connecting string35, at the end facing away from the trolley 21, is provided with asecond connector device which can be releasably connected to the firstconnector device. When the first and second connector devices arecoupled together, the different pipes or lines of the connecting string35 are connected. This will be explained in more detail below.

The connecting string 35 is configured such that the trolley 21 cantravel over the floor 71 of the animal-free space 70 into each of themilking stations 10, while the trolley 21 remains connected to thecoupling device 36 by means of the connecting string 35. For example,the length and stiffness of the connecting string 35 are adapted suchthat the trolley 21 can travel into each milking station 10, up to belowthe teats of a cow 8. In this exemplary embodiment, the connectingstring 35 is guided in the animal-free space 70 through an eye of astring guide 37 which is movably suspended on a guide rail 38. In thisway, the connecting string 35 does not obstruct the trolley 21 in itstravel over the floor 71. Such a string guide is however optional.

Although the connecting string 35 in FIGS. 4a-4d is indicateddiagrammatically by a single solid line, the connecting string 35 inthis exemplary embodiment comprises several pipes or lines, as indicateddiagrammatically in FIG. 7. The various pipes or lines of the connectingstring 35 are described below.

The connecting string 35 comprises four milk lines 80 a, 80 b, 80 c, 80d. The four milking cups 22, known in themselves, of the trolley 21 eachcomprise a teat space and a pulsation space (not shown). In thisexemplary embodiment, each milking cup 22 is connected by means of adouble-channel hose 66 to a coupling piece 55 which is attached to thetrolley 21. Each double-channel hose 66 comprises two channels (notshown). The one channel of the double-channel hose 66 is a milk-carryingchannel which discharges a mixture of milk and air from the milking cup22, while the other channel of the double-channel hose 66 forms a vacuumchannel for application of a pulsating vacuum to the teat space of themilking cup 22. The vacuum channel is connected via the coupling piece55 to a pulsator (not shown), which is attached to the trolley 21.

The four milk lines 80 a, 80 b, 80 c, 80 d of the connecting string 35are connected at one end via the coupling piece 55 to the respectivemilk-carrying channels of the double-channel hoses 66. At the other end,the milk lines 80 a, 80 b, 80 c, 80 d are connected to the couplingdevice 36. The four milk lines 80 a, 80 b, 80 c, 80 d are eachconnected, via the mutually coupled first and second connector devicesof the coupling device 36 and the connecting string 35 respectively,fluid-tightly and/or air-tightly to four milk-carrying lines 57 a, 57 b,57 c, 57 d which are connected to a milk/air separator 33 for separatingmilk and air (see FIG. 2). The milk/air separator 33 is formed forexample by a milk jar known in itself. The milk/air separator 33 isfixedly arranged in the animal-free space 70.

The milk/air separator 33 is in fluid connection via a milk transportline 34 with a milk storage tank 25 for the cooled storage of milk. Themilk storage tank 25 is fixedly placed outside the accommodation space2, for example in the animal-free space 70 or elsewhere. The milktransport line 34 comprises a milk pump 32 which transports milk fromthe milk/air separator 33 to the milk storage tank 25. Between the milkpump 32 and the milk storage tank 25, the milk transport line 34comprises a three-way valve 27 for separating pre-milk and/or milk whichis unsuitable for human consumption.

The connecting string 35 furthermore comprises a flexible vacuum line 81which is in fluid connection with the pulsator attached to the trolley21. The flexible vacuum line 81 connects the pulsator of the trolley 21to the coupling device 36. The flexible vacuum line 81 is connected, viathe mutually coupled first and second connector devices of the couplingdevice 36 and the connecting string 35 respectively, air-tightly to avacuum line 59 which leads to a vacuum source 26. The vacuum source 26is placed at a fixed location in the animal-free space 70. The vacuumsource 26 is for example configured as a vacuum pump, known in itself,with rotation speed control. The vacuum source 26 is furthermoreconnected by means of a vacuum line 58 to the milk/air separator 33.

In addition, the connecting string 35 comprises a flexible power supplyline 85. The power supply line 85 forms part of an electrical connectionbetween the trolley 21 and an electrical power source 31, for example ahigh-voltage current source. The trolley 21 comprises several electricmotors. For example, the trolley 21 in this exemplary embodiment has adrive and steering system for driving and steering the trolley 21. Thetrolley 21 has two tracks 73, and for each track 73 a respectiveelectric motor is arranged on the trolley 21 (not shown). In addition,the trolley 21 comprises electric motors for moving the milking cups 22relative to the trolley 21 so that the milking cups 22 can be connectedautomatically to the teats of a cow 8. For teat detection, the trolley35 furthermore comprises a camera 74, in particular for producingthree-dimensional images. Instead of the camera 74, other teat detectionmeans may also be used. The electric motors and the camera 74 on thetrolley 35 are supplied with electrical energy which is supplied via theflexible power supply line 85. At the coupling device 36, the powersupply line 85 is connected to a supply cable 64, for example by meansof plugs. The trolley 21 in this exemplary embodiment requires noelectrical accumulators.

The connecting string 35 furthermore comprises a flexible water line 82,for example a water hose, which is connected at one end to the trolley21. On the trolley 21, water is used for example to rinse the milkingcups 22 after milking. The water line 82 is in fluid connection with themilking cups 22 on the trolley 35 (not shown). At the other end, thewater line 82 is connected, via the mutually connected connector devicesof the connecting string 35 and the coupling device 36, fluid-tightly toa water supply line 62 which is connected to a water connection 29. Thewater connection 29 is formed for example by a tap connected to thewater mains.

The connecting string 35 is furthermore provided with a flexiblecompressed air line 83. Compressed air is used for example on thetrolley 21 to blow clean a lens of the camera 74 or the milking cups 22of the trolley 21. The compressed air line 82 is connected at one end tothe trolley 21, for example in fluid connection with a nozzle providedon the trolley 21 (not shown). At the other end, the compressed air line82 is connected, via the mutually connected connector devices of theconnecting string 35 and coupling device 36, air-tightly to a compressedair line 61 which is connected to a compressed air source 28.

The connecting string 35 has a flexible data line 86, for example anethernet cable, which is connected at one end to a control unit arrangedon the trolley 21 (not shown). The data line 86 is connected via thecontrol unit of the trolley 21 to the camera 74 of the trolley 35. Inthis exemplary embodiment, the image signal from the camera 74 istransmitted by the control unit of the trolley 35, via the data line 86,the connected connector devices of the connecting string 35 and of thecoupling device 36, and a data cable 65, to the control system 41. Onthe basis of the image signal of the camera 74, the control system 41can determine the position of the teats of a cow 8. Via the hard-wireddata connection 65, 86, control signals can furthermore be sent by thecontrol system 41 to the control unit on the trolley 21. The drive andsteering system of the trolley 21 is controlled depending on the controlsignals. Data are sent from the trolley 21 to the control system 41 andvice versa via the hard-wired data connection.

In this exemplary embodiment, the connecting string 35 comprises aflexible fluid line 84 for disinfectant fluid, which is in fluidconnection with a spray device arranged on the trolley 21 for sprayingdisinfectant fluid onto the teats of a cow 8. The fluid line 84 fordisinfectant fluid is connected in the same manner as described above,via the coupling device 36 and an associated line 63, to a holder 30 fordisinfectant. The sprayer device is aimed for example at one or morebrushes for pretreatment of the teats of a cow 8 which must be milked.Instead of pretreatment with brushes, the trolley 21 may contain apretreatment cup for pretreatment of the teats. In this case, the fluidline 84 is connected to the pretreatment cup of the trolley 21.

Also, one or more of the pipes or lines described above of theconnecting string 35 may be omitted. For example, the trolley 21comprises a holder for disinfectant, so that disinfectant need not besupplied to the trolley 21 and the fluid line 84 is not required. Inaddition to the pipes or lines described above, the connecting string 35may also comprise other pipes or lines and/or cables.

The milking cups 22 of the trolley 21 are arranged on a robot arm 75which is movable between a lowered state (see FIGS. 4a-4c ) and a raisedstate (see FIG. 4d ). In this exemplary embodiment, the robot arm 75 isconnected to a chassis of the trolley 21, pivotably between the loweredstate and the raised state. The robot arm 75 can be driven by means ofan electric drive motor (not shown) which is actively connected with thecontrol system 41. The milking cups 22 of the trolley 35 are tiltablerelative to the robot arm 75 between a retracted state (see FIGS. 4 a-c)and an erected state (see FIG. 4d ). In the retracted state, the milkingcups 22 lie substantially horizontally, with the openings of the milkingcups 22 opposite the direction of travel of the trolley 21, while in theerected state the milking cups 22 are tilted upward, for exampleextending substantially vertically upward. In this exemplary embodiment,the milking cups 22 are pretensioned in the erected state, for exampleby means of a spring means, and the trolley 21 comprises a tilt drivefor tilting the milking cups 22 from the erected state to the retractedstate (not shown). The tilt drive comprises an electric drive motor (notshown). The tilt drive is actively connected to the control system 41.

As shown most clearly in FIGS. 4a-4d , the milking stations 10 eachcomprise a floor with a first floor part 90 and a second floor part 91which is raised relative to the first floor part 90. The first floorpart 90 is connected below the second floor part 91 to the floor 71 ofthe animal-free space 70. In this exemplary embodiment, the floor 71 ofthe animal-free space 70 and the first floor part 90 form a cohesivefloor. The trolley 21 can travel over the flat floor 71 of theanimal-free space 70, under the second floor part 91, onto the firstfloor part 90 of each milking station 10.

The raised second floor part 91 is arranged for example 20 cm higherthan the first floor part 90. Such a raised position corresponds inprinciple to the normal height difference between a lying stall and thefloor in a barn. The length of the second floor part 91, viewed in thelongitudinal direction of each milking station 10, is such that when acow 8 stands in the milking station 10 with its front legs on the secondfloor part 91, the rear legs of said cow 8 stand on the first floor part90. The length of the second floor part in this exemplary embodiment is50 cm. A cow 8 in a milking station 10 can only drink from the drinkingtrough 17 of said milking station if the cow 8 stands with its frontlegs on the second floor part 91. When the cow 8 stands with its frontlegs on the second floor part 91, the cow 8 has a position and/orattitude which is suitable for connecting the milking cups 22 of thetrolley 21 to the teats of said cow 8.

When a cow 8 visits one of the milking stations 10 to drink from thedrinking trough 17 and said cow 8 is ready for milking, the controlsystem 41 controls the trolley 21 so that the trolley 21 travelsautomatically over the floor 71 of the animal-free space 70, onto thefirst floor part 90 of said milk station 10, to under the teats of saidcow 8. Since only a restricted height is available under the secondfloor part 91, the trolley 35 with erected milking cups 22 is unable totravel below the second floor part 91, even if the robot arm 75 islowered.

To enable the trolley 21 to travel from the floor 71 of the animal-freespace 70, under the fence 14 and the second floor part 91, the milkingcups 22 of the trolley 21, with the robot arm 75 in the lowered state,are tilted down into the retracted state. The trolley 21 then fits underthe second floor part 91 (see FIG. 4c ). After the trolley 21 has passedunder the second floor part 91, the control system 41 controls theelectric drive motor of the robot arm 75 to bring this into the raisedstate, and the tilt drive to move the milking cups 22 to the erectedstate. Then the milking cups 22 are connected automatically to the teatsof the cow 8 on the basis of control signals from the control system 41.The trolley 21 can be moved inside the milking station 10 and/or therobot arm 75 can be controlled relative to the trolley 21 to connect themilking cups 22 automatically to the teats of a cow 8 in the milkingstation 10.

During travel over the floor 71 of the animal-free space 70, and up tothe first floor part 90 of the milking station 10, the trolley 21remains connected to the coupling device 36 by means of the flexibleconnecting string 35. Since the pipes or lines of the connecting string35 are used to discharge the milk, to supply a vacuum, water, compressedair and disinfectant, and to exchange data, the trolley 21 can beconfigured particularly light and compact.

Also, in an embodiment not shown, according to the invention it ispossible that milk and air discharged from the milking cups 22 areseparated from each other on the trolley 21. For example, the milkingcups 22 are each connected to a milk/air separator which is arranged onthe trolley 21. The milk/air separator of the trolley 21 has a milkdischarge opening which is in fluid connection with a milk pump arrangedon the trolley 21. The milk pump is connected to a single flexible milkline which extends through the connecting string 35 to the couplingdevice 36. Only milk flows through the flexible milk line of theconnecting string 35. Only one milk line is required for transportingthe milk. The milk is discharged from the coupling device 36 to the milkstorage tank 25 as described above. Since the milk pump in this case isarranged on the trolley 21, the milk can be transported from the trolley21 to the milk storage tank 25 particularly efficiently.

In a further embodiment (not shown), according to the invention, thesystem comprises two or more autonomous self-propelled trolleys. Forexample, a second trolley contains a device for pretreatment and/orpost-treatment of the teats of a cow 8 in a milking station 10. Thesecond trolley can pretreat, for example clean, disinfect and/orstimulate, the teats of the cow 8 in a milking station 10, before thefirst trolley 21 automatically connects the milking cups 22 to theteats. In addition or alternatively, the second trolley may beconfigured to post-treat the teats of the milk cow 8, i.e. after thefirst trolley 21 has milked the cow 8 and travelled away, the secondtrolley travels under the milk cow 8 for post-treatment. Thereforefirstly the pretreatment and/or post-treatment, and secondly themilking, are carried out by different trolleys. Also, a second trolleymay be configured in the same way as the first trolley.

An alternative embodiment of the system is shown in FIGS. 5, 6 a-6 c.The same or similar components carry the same reference numerals. Inthis case, the system comprises a telescopic robot arm 100. Thetelescopic robot arm 100 comprises several arm parts 101 a, 101 b, 101c, 101 d which are telescopically connected to each other. By extendingand retracting the arm parts 101 a, 101 b, 101 c, 101 d, the robot arm100 can be moved in the longitudinal direction of the milking station10. The first arm part 101 a of the robot arm 100 is fixed to an armguide 105 which is connected to a fixed supporting structure. In thisexemplary embodiment, the supporting structure comprises a guide rail106 connected to the floor 71 of the animal-free space 70. The arm guide105 with the robot arm 100 attached thereto is guided movably over theguide rail 106 by means of rollers, in the transverse direction of themilking stations 10. The function of the robot arm 100 is furthermoresubstantially the same as that of the trolley 21 described above, andwill not therefore be explained further. It is also possible that theflexible connecting string 35 on the robot arm 100 is configureddifferently, for example is replaced by pipes, lines and/or cables whichare arranged on the robot arm 100.

Although the guide rail 106 in this exemplary embodiment is attached tothe floor 71 of the animal-free space 70, the guide rail 106 for the armguide 105 may also be suspended. The robot arm 100 may furthermore,instead of a telescopic arm, also be configured as a robot arm withseveral arm parts connected pivotably relative to each other (notshown). Instead of a robot arm 100 which can perform a rectilinearmovement transversely relative to the milking stations 10, according tothe invention it is also possible that the robot arm is connected to afixed supporting structure about a substantially vertical pivot axis,for example by means of a ball joint. In this case, the milking stationsmay be placed around the pivot axis, i.e. the milking stations then lielaterally next to each other in an arc, such that the milking stationsare oriented with their head sides substantially towards the pivot axis.By pivoting the robot arm, the robot arm can be aligned with each of themilking stations so that the robot arm can connect milking cups in eachmilking station. Such robot arms for connection of milking cups 22 maybe designed and produced using techniques known in themselves inpractice.

The robot arm 100 shown in FIGS. 5, 6 a-6 c is provided with milkingcups 22. The milking cups 22 are arranged on the robot arm 100. Duringoperation, the robot arm 100 connects the milking cups 22 one by one tothe teats of a cow 8. It is however also possible that the milkingsystem 20 is provided with a milking cup holder (not shown), configuredfor holding the milking cups 22 which are not being used. The robot arm100 in this case comprises a gripper member (not shown), which isconfigured to take at least one milking cup 22 from the milking cupholder and connect this to a teat of a cow 8. During operation, therobot arm 100 takes a first milking cup 22 from the milking cup holderand connects said milking cup to a teat, then the robot arm 100 takes asecond milking cup 22 from the milking cup holder, and so on. Also, sucha robot arm can be produced using techniques known in themselves inpractice. The milking cup holder with a set of milking cups 22 may bearranged in the animal-free space 70, or such a milking cup holder witha set of milking cups 22 may be arranged in each milking station 10.With such a robot arm 100, each milking station 10 may comprise a set ofmilking cups 22. The milking cups 22 are for example arranged in sets inthe animal-free space 70 in front of each milking station 10 or in eachmilking station 10, for example close to the teats of a cow 8. It isalso possible that a common set of milking cups 22 is shared by severalmilking stations 10. The milking cups 22 are then used successively inseveral milking stations 10.

After a cow 8 has been milked, in the exemplary embodiments describedabove, said cow 8 may remain in the milking station until the cow 8voluntarily leaves the milking station, unless the cow 8 complies with apredefined expulsion criterion and all milking stations 10 are occupiedby other cows. As indicated diagrammatically in the figures, eachmilking station 10 comprises an expulsion means 110 for driving a cow 8out of the milking station 10. The expulsion means 110 may be activated,in each of the milking stations 10, to give an expulsion stimulus to amilking animal present in the milking station 10, to encourage it toleave the milking station 10. The expulsion means 110 may be configuredin various ways, for example for administering an electric shock to acow 8 in the milking station 10. Alternatively or additionally, theexpulsion means 110 may be configured to give a cow 8 an expulsionstimulus in the form for example of a light signal, an audible signal ora contact signal, such as by means of a water-jet, an air pulse, or amechanical push or contact element. Also, according to the invention itis possible that the expulsion means are movable relative to the milkingstations 10, such that an expulsion stimulus can be given in eachmilking station 10 to a cow 8 present in said milking station 10 (notshown). Furthermore, according to the invention it is possible that thesystem 1, instead of or in addition to the expulsion means 110, has anattraction means and/or other motivation means for giving a stimulus inorder to entice the cows 8 to leave the milking stations, for example bymeans of feed concentrate.

To be able to activate the expulsion means, the expulsion means 110 areeach actively connected to the control system 41. The control system 41controls the expulsion means 110 such that the expulsion means 110 areonly activated if two conditions are fulfilled: (i) a cow 8 in one ofthe milking stations 10 fulfils the predefined expulsion criterion, and(ii) all milking stations 10 are occupied. The expulsion criterion maycomprise different parameters. For example, the expulsion criterion isdependent on the milking criterion, such as whether the cow 8 fulfilsthe milking criterion or fulfils the milking criterion within apredefined period, and/or the visit behavior of the cow 8, such as theexpected time between two successive visits of the cow 8 to the milkingstations, and/or the drinking behavior of the cow 8, such as the waterintake, i.e. how much the cow 8 drinks from the drinking trough, and/orother parameters. The expulsion criterion may furthermore be determinedindividually for each individual cow 8 in the accommodation space 2.Also with a cow-dependent milking criterion however, an expulsioncriterion may be used which is the same for all cows 8 in theaccommodation space 2.

As described above, the number of milking stations 10 according to theinvention is selected such that it does not occur or rarely occurs thatall milking stations 10 are occupied simultaneously, i.e. duringoperation, almost always one or more milking stations 10 are free. Sincea cow 8 is only expelled from the milking station if condition (ii) isfulfilled, i.e. all the milking stations are occupied, a cow 8 is drivenout only in very exceptional cases. This has a positive effect on theextent to which the cows 8 voluntarily visit the milking stations 10.The system according to the invention is configured to allow every cow 8visiting a milking station 10 to remain there in principle until saidcow 8 voluntarily leaves the milking station. The milking animals areonly subjected to expulsion stimuli, which are perceived by the cows 8as uncomfortable, in the exceptional circumstance that all milkingstations 10 are occupied. In addition, the control system 41 alsodetermines whether the cow 8 to be driven out complies with thepredefined expulsion criterion.

Instead of driving out cows by means of the expulsion means 110 only invery exceptional circumstances, according to the invention it is alsopossible to allow the cows always to remain in the milking stationsuntil the cows voluntarily leave the milking stations. In this case, noexpulsion means 110 are required, i.e. the expulsion means 110 areomitted in this embodiment (not shown). None of the milking stations 10comprises expulsion means. Also, the system does not comprise anyattraction means or other motivation means for encouraging the cows 8 toleave the milking stations. The cows 8 may remain in the milkingstations 10 until the cows 8 voluntarily leave the milking stations 10.As described above, the cows 8 have access to the milking stations 10irrespective of whether or not the cows 8 fulfil the milking criterion,i.e. irrespective of whether the cows 8 must be milked. Both cows 8which have been milked, and cows 8 which visit the milking stations 10to drink without needing to be milked, may remain in the milkingstations 10. In this case, it cannot be completely excluded that allmilking stations 10 are occupied at some time by the cows 8. If allmilking stations 10 are occupied, a cow 8 from the accommodation space 2which wishes to drink, must wait until one of the cows 8 voluntarilyleaves the milking station 10. As explained above, the number of milkingstations 10 is however sufficiently great, relative to the number ofcows 8 contained in the accommodation space 2, that the risk is minimalthat all milking stations 10 will remain occupied simultaneously for anunacceptable period.

An alternative embodiment of the system shown in FIG. 8. The same orsimilar components carry the same reference numerals. In the embodimentshown in side view of FIG. 8, the animal-free space also comprises alowered floor 200 which extends below the level of the connectionthrough which the trolley 21 can travel, whereby the animal-free spaceis lowered relative to the milking stations 10. Thus the system stillcomprises the animal-free space 70 which is closed for the milkinganimals 8 and extends adjacent to the milking stations 10, and whereinthe floor 90 of the milking station 10 is connected to the floor 71 suchthat the trolley can travel from the animal-free space 70 via floor 71to the floor part 90 of the milking station. However, the animal-freespace in addition has the lowered floor 200 which lies below the levelof the floor 71 and the floor part 90 over which the trolley can travel.The lowered floor extends under both the floor 71 over which the trolleycan travel and partly also below the floor part 90 of the milkingstation. In practical terms, the animal-free space is thus lowered belowthe level of the milking stations, which makes this particularlysuitable for use in existing milking carousels or milking pits, with fewconversion measures. A milking carousel or milking pit already has ananimal-free space with a floor which is lower than the floor of themilking stations. Maintenance of the trolley 21 is now easy to implementbecause personnel standing on the lowered floor 200 of the animal-freespace can easily reach the level of the floor 71 with the trolley 21.The floor over which the milking animals can walk is indicated with thedotted line 291, and connects the milking station 10 to another part ofthe accommodation space 2. This walkable floor 291 lies above the floor71 on which the milking trolley can travel, and extends further abovethe animal-free space. The animal-free space can thus be configured as acellar; in FIG. 8 the walls of such a cellar are not shown. The roof ofthe cellar is, at least partly, formed by this floor 291. The roof 291connects to the accommodation space, whereby the animals can walk fromthe milking station via the cellar roof to the accommodation space. InFIG. 8, the milking animal can walk from the milking station 10 straightover the raised floor part 91 and via a closable passage (not shown) atthe end of the milking station, over the walkable floor 291, to anotherpart of the accommodation space 2, or to a further accommodation space,such as a separation space or a grazing space (not shown).

The invention is not restricted to the exemplary embodiments shown inthe drawing. The person skilled in the art may make various adaptationswhich lie within the scope of the invention. The features describedabove may be used both separately and in any arbitrary combination,and/or be combined with one or more features according to one or more ofthe claims which follow. In particular, according to the invention, thedrinking system with drinking troughs 17 may be replaced by a feedand/or drinking system for providing feed and/or water for the milkinganimals. The feed and/or drinking system comprises for example a feedand/or drinking trough for each milking station. The milking animalsthen visit the milking stations to eat and/or drink. Furthermore,according to the invention, it is possible that the system, instead ofthe neck lock device described in the description and claims, comprisesanother holding device for securing and/or holding a milking animal in amilking station. For example, each milking station has a holding devicewhich can be operated by means of an actuator device between a holdingstate, in which a milking animal present in said milking station is heldby the holding device, and a free state, in which a milking animalpresent in said milking station is free to leave said milking station.Such a holding device for example comprises a door or gate to enclose amilking animal in a milking station, such as in a generally knownmilking stall.

The invention claimed is:
 1. A system for milking a group of milkinganimals wherein the system comprises: an accommodation space for themilking animals, the accommodation space is stationary and has a fixedfloor, a milk storage tank, an automatic milking system for automaticmilking of milking animals, wherein the milking system comprises atleast one autonomous, self-propelled trolley with milking cups, andwherein the milking system is configured for the automatic connection ofthe milking cups of the trolley to the teats of a milking animal, andwherein the milking cups of the trolley are connected to the milkstorage tank by means of a milk discharge system, the milk dischargesystem includes a flexible milk line connected to the trolley, thesystem further comprises: a plurality of milking stations each arrangedat a fixed position relative to the fixed floor and next to each other,wherein the milking stations each comprise an entry opening for entry ofa milking animal from the accommodation space to said milking station,an animal-free space closed for the milking animals in the accommodationspace and extends adjacent to the milking stations, wherein theanimal-free space is connected to each milking station by a connection,the trolley being configured to travel from the animal-free space toeach milking station via the connection, and wherein the milk storagetank is placed at a fixed position outside the accommodation space, andthe flexible milk line is configured such that the trolley can travelfrom the animal-free space into each of the milking stations while themilk line remains connected to the trolley.
 2. The system as claimed inclaim 1, wherein the milk discharge system is provided with a pluralityof flexible milk lines, the plurality of flexible milk lines are eachconnected at one end to the trolley and are each in fluid connectionwith one of the milking cups, and a milk/air separator arranged in theanimal-free space, and wherein each milking cup of the trolley isconnected respectively via one of the flexible milk lines to themilk/air separator, and wherein the flexible milk lines are eachconfigured such that the trolley can travel from the animal-free spaceinto each of the milking stations while the milk lines each remainconnected to the trolley.
 3. The system as claimed in claim 1, whereinthe milk discharge system comprises a milk/air separator arranged on thetrolley, and wherein the milking cups are each connected to the milk/airseparator, and wherein the milk/air separator comprises a milk dischargeopening in fluid connection with the end of the flexible milk lineconnected to the trolley, and wherein the trolley is provided with amilk pump for pumping milk via the flexible milk line to the milkstorage tank.
 4. The system as claimed in claim 1, wherein the milkingsystem comprises a vacuum source arranged in the animal-free space,wherein the vacuum source is connected via a vacuum system to themilking cups for applying a vacuum to the milking cups, and wherein thevacuum system comprises a flexible vacuum line connected to the trolleyand is configured such that the trolley can travel from the animal-freespace into each of the milking stations while the vacuum line remainsconnected to the trolley.
 5. The system as claimed in claim 1, whereinthe milking system comprises an electric power supply source arranged inthe animal-free space, and wherein the trolley is connected to the powersupply source by means of an electrical connection, wherein theelectrical connection comprises a power supply line connected at one endto the trolley and is configured such that the trolley can travel fromthe animal-free space into each of the milking stations while the powersupply line remains connected to the trolley.
 6. The system as claimedin claim 1, wherein the milking system comprises a water connectionarranged in the animal-free space, and wherein the trolley is connectedto the water connection by means of a water supply system comprising aflexible water line connected at one end to the trolley and isconfigured such that the trolley can travel from the animal-free spaceinto each of the milking stations while the water line remains connectedto the trolley.
 7. The system as claimed in claim 1, wherein the milkingsystem comprises a compressed air source arranged in the animal-freespace, and wherein the trolley is connected to the compressed air sourceby means of a compressed air system comprising a flexible compressed airline connected to the trolley and is configured such that the trolleycan travel from the animal-free space into each of the milking stationswhile the compressed air line remains connected to the trolley.
 8. Thesystem as claimed in claim 1, wherein the milking system comprises acontrol system, and wherein the trolley is connected to the controlsystem by means of a hard-wired data connection comprising a flexibledata line, the flexible data line is connected to the trolley and isconfigured such that the trolley can travel from the animal-free spaceinto each of the milking stations while the data line remains connectedto the trolley.
 9. The system as claimed in claim 1, wherein the milkingsystem is provided with a coupling device, the coupling device isarranged at a fixed position in the animal-free space, and wherein thetrolley is connected to the coupling device by means of a flexibleconnecting string configured so that the trolley can travel from theanimal-free space into each of the milking stations while the connectingstring remains connected to the trolley, and wherein the connectingstring comprises the milk line and/or a vacuum line and/or a powersupply line and/or a water line and/or a compressed air line and/or adata line.
 10. The system as claimed in claim 9, wherein the couplingdevice comprises a first connector device, and wherein the flexibleconnecting string, at an end remote from the trolley, is provided with asecond connector device, the second connector device is configured to bereleasably coupled to the first connector device for connecting the milkline and/or the vacuum line and/or the power supply line and/or thewater line and/or the compressed air line and/or the data line.
 11. Thesystem as claimed in claim 1, wherein the animal-free space alsocomprises a lowered floor extending below the level of the connection,wherein the animal-free space is lowered relative to the milkingstations.
 12. The system as claimed in claim 1, wherein the animal-freespace comprises a floor, and wherein each milking station comprises afloor provided with a first floor part connected to the floor of theanimal-free space so that the trolley can travel from the floor of theanimal-free space to the first floor part of said milking station andback, and a second floor part raised relative to the first floor part,and wherein the trolley is configured to travel from the floor of theanimal-free space at each milking station, under the second floor part,to the first floor part of said milking station and back.
 13. The systemas claimed in claim 12, wherein the milking cups of the trolley can betilted between a retracted state such that the trolley with the milkingcups can travel under the second floor part, and an erected state suchthat the milking cups are tilted up relative to the retracted state. 14.The system as claimed in claim 12, wherein the milking stations compriseat least one feed and/or drinking trough, the feed and/or drinkingtrough is arranged at the head ends of the milking stations opposite theentry openings, such that the milking animal present in one of themilking stations must stand with its front legs on the second floor partof said milking station in order to eat and/or drink from the feedand/or the drinking trough.
 15. The system as claimed in claim 1,wherein the system is provided with a second autonomous, self-propelledtrolley provided with a device for pretreatment and/or post-treatment ofthe teats of a milking animal present in a milking station.
 16. Thesystem as claimed in claim 1, wherein the accommodation space comprisesa resting area with lying stalls for the milking animals, and whereinthe system comprises at least one milking station for every 20 lyingstalls.
 17. A method for milking a group of milking animals in a systemas claimed in claim 1, and wherein the method comprises: identificationof a milking animal in one of the milking stations, determining whethersaid milking animal complies with a predefined milking criterion, whensaid milking animal complies with the predefined milking criterion:travel of the trolley from the animal-free space to said milkingstation, automatic connection of the milking cups of the trolley to theteats of said milking animal, milking of said milking animal by means ofthe milking system in said milking station, disconnection of the milkingcups from the teats of said milking animal, return of the trolley fromthe milking station to the animal-free space.
 18. The method as claimedin claim 17, wherein a coupling between a first connector device of acoupling device and a second connector device of a connecting string isreleased, and the trolley with the connecting string is then replaced bya second trolley with a second connecting string corresponding to aconnecting string of the replaced trolley, wherein the second connectordevice of the second connecting string of the second trolley isreleasably coupled to the first connector device of the coupling device.